With the development of semiconductor lighting technology (LED), such revolutionary new light source has come into our daily life gradually. When the third generation semiconductor material gallium nitride is used as the semiconductor lighting source, its power consumption is only one-tenth of that of a common incandescent lamp under the same brightness; its lifetime can reach more than 1 million hours as well. As a new-type lighting technology, LED can be applied into varieties of fields such as indication, display, decoration, backlight and general lighting due to its numerous advantages including energy conservation, green environmental protection and flexible application etc., which is to bring about a revolution in the lighting field. Therefore, there is an urgent need for an efficient fluorescent material, which is capable of converting the blue-purple light emitted by light-emitting components including LED into the visible light, thus achieving white-light and multi-color light-emitting devices.
In the prior art, a main approach for achieving the white light emission of LED is through the cooperation of a blue-light LED chip and a rare earth garnet yellow fluorescent powder (such as YAG:Ce3+ or TAG:Ce3+) which is excited by cerium. However, the white light spectrum implemented by such method is short of green and red element, thus leading to two obvious disadvantages namely low color rendering property and high color temperature. In order to solve the disadvantages mentioned above, on one hand, green fluorescent powder or red fluorescent powder is doped into the yellow fluorescent powder excited by blue-light LED chip. On the other hand, an ultraviolent LED chip is used for exciting the red-green-blue tribasic fluorescent powder to enhance the color rendering property and regulate the color temperature. Although the above-mentioned two approaches can solve the problems of color rendering property and color temperature of light source relatively well, it still is required to encapsulate the LED chip after mixing various fluorescent powders with resin. During this process, the problem lies in that different kinds of fluorescent powders may not be mixed uniformly, which causing the non-uniform color of produced white light and influencing its practicability seriously.